Will the cost of gas bleed your travel budget dry?

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Americans love road trips. In 2011, AAA estimated that 32.8 million Americans drove a distance of 50 miles (80.5 kilometers) or greater during the Fourth of July weekend [source: AAA]. While that's an impressive figure, it's nearly a million less than the number of travelers that hit the road in 2010. Why? The price of gasoline. The national average for a gallon of regular unleaded jumped nearly a dollar a gallon from the previous year, from about $2.70 to $3.60 [source: AAA]. The high cost of fuel doesn't have to stall your plans, though. It's easy to minimize the amount of gasoline you'll use on your trip and calculate about how much it will cost you, ensuring your drive is both affordable and carefree.

There are several steps you can take to reduce your gasoline before you even pull out of the driveway. When planning a long road trip, it's a good idea to have a mechanic change the oil and fix any problems that may exist. Repairing a car that's out of tune can improve fuel efficiency by an average of 4 percent, while fixing a faulty oxygen sensor can increase gas mileage by a whopping 40 percent. You should also check to ensure that your tires are properly inflated. For each pound per square inch that your tires are underinflated, your fuel economy is reduced by 0.3 percent [source: EPA]. Finally, pack light. Every 100 pounds added to a car's weight results in a 2 percent reduction in gas mileage, and tying luggage to the top can lead to a decrease of up to 21 percent [source: EPA, Valdes-Dapena].

Once you're on the road, there are more ways to reduce how much gas goes in the tank. Consider taking scenic back roads with lower speed limits; fuel efficiency is dramatically reduced at speeds greater than 60 miles per hour (96.5 kilometers per hour) [source: EPA]. On flatter stretches of road, use the cruise control. Allowing the car to decide when to apply acceleration instead of doing it yourself can increase gas mileage by 10 to 15 percent [source: Valdes-Dapena]. Timing your route properly can also save fuel. Stay away from big cities during rush hour when stop-and-go traffic can bring your progress to a standstill and reduce your gas tank to vapors. Consider investing in a GPS unit or mobile phone app like Google Maps, which can actually display traffic congestion in real time, allowing you to plan a detour far in advance of any problems.

While these tips can reduce your gasoline usage, they won't completely eliminate it, so it's still nice to know about how much fuel you will use on your road trip. Read on to learn how to calculate what your drive will cost.